1. Field of the Invention
The present invention relates to a semiconductor device which performs reception/transmission of a data by wireless communication. Further, the present invention relates to a semiconductor device having a function of operating a protection circuit and a modulation circuit with one circuit, in which the protection circuit prevents degradation and breakdown of elements of a chip in the semiconductor device particularly when a large amount of electric power is received in wireless communication, and the modulation circuit is operated by data transmission.
2. Description of the Related Art
In recent years, an individual identification technology using wireless communication (hereinafter referred to as a wireless communication system) has attracted attention. In particular, an individual identification technology with a semiconductor device utilizing an RFID (radio frequency identification) technology as a data carrier which transmits/receives data by wireless communication has attracted attention. Such a semiconductor device which can transmit/receive data by wireless communication can be used as, for example, an RF tag (also called an IC (integrated circuit) tag, an IC chip, an RFID tag, a wireless tag, or an electronic tag) and has started to be used for production, management, or the like of an individual object and application thereof to personal authentication is also advancing.
A wireless communication system herein is a communication system which wirelessly exchanges data between a power supply source also serving as a transceiver such as a reader/writer and a transceiver such as a semiconductor device.
The wireless communication system does not need a physical connection between the reader/writer and the semiconductor device. That is, as long as the semiconductor device exists in a region designated by the reader/writer, a data can be exchanged by communication between the reader/writer and the semiconductor device.
In order to extend the communication distance between the reader/writer and semiconductor device, research and development for increasing the power supply efficiency from the reader/writer to the semiconductor device has been activated (e.g., reference 1: Japanese Published Patent Application No. 2006-5651).